1. Field of the Invention
The present general inventive concept relates to a cleaning robot, and more particularly to a cleaning robot having a corner cleaning unit to clean a corner adjacent to a wall, and a method thereof.
2. Description of the Related Art
A conventional cleaning robot is a cleaning apparatus that draws foreign materials such as dust from a floor while independently traveling in a cleaning area. The cleaning robot having a corner cleaning unit for cleaning a corner adjacent to a wall is disclosed in Japanese Patent Application Publication No. 2004-337301.
The corner cleaning unit disclosed in this document includes a suction member that is rotatably coupled to a main body to be unfolded outwards and is provided with a suction port at a lower portion thereof, and a rotational support that rotatably supports the suction member. The rotational support is provided with spiral guide slots on an inner surface thereof to allow the suction member to be raised and lowered by means of rotation, and the suction member is provided with protrusions inserted into the guide slots. Further, a torsion spring is interposed between the suction member and the rotational support.
With the above construction, the suction member can be unfolded by the elasticity of the torsion spring to maintain the unfolded state.
In the above corner cleaning unit, because the protrusions of the suction member are guided to be lowered by the guide slots of the rotational support when the suction member is unfolded outwards by means of rotation, the suction member is lowered. In contrast, because the suction member is rotated in an opposite direction when the suction member is folded toward the main body, and the protrusions of the suction member are guided to be raised by the guide slots of the rotational support, the suction member is raised.
However, the corner cleaning unit of the cleaning robot is adapted to allow the suction member to be rotated and folded when the suction member collides with an obstacle (e.g. the leg of a sofa, the leg of a chair, etc.) while the main body is traveling. In this case, the suction member is raised, and is greatly separated from the floor. As a result, a cleaning effect is degraded.
Further, when the cleaning robot travels on an uneven floor like a carpet, its wheels are buried under the surface of the carpet by means of the weight of the main body, the suction member is not sufficiently unfolded, and thus all the desired corner regions cannot be covered. Moreover, when the corner cleaning unit is not used, the suction member must be manually rotated and folded. Thus, the cleaning robot is inconvenient to use.